In recent years, in a luminaire, as an illumination light source, an incandescent lamp or a fluorescent lamp is being replaced by an energy-saving and long-lived light source, for example, a light-emitting diode (LED). Besides, a new illumination light source such as, for example, an EL (Electro-Luminescence) or an organic light-emitting diode (OLED), is also developed. A luminaire is known in which the light-emitting element is connected with a capacitive element such as a capacitor and is stably lit without flickering. In the luminaire as stated above, when the power supply is changed over as in, for example, an emergency lamp, there is a possibility that current flows back from the capacitor to the power supply side, and a power supply circuit is erroneously operated.
An exemplary embodiment described herein provides a luminaire which does not erroneously operate even when a capacitive element is connected as a load.